994
FXUS21 KWNC 041936
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST JANUARY 04 2026
SYNOPSIS: AT THE START OF WEEK-2, A TIGHT GRADIENT BETWEEN HIGH SURFACE
PRESSURE OVER THE INTERIOR WEST AND LOW PRESSURE FARTHER SOUTH INCREASES THE
ODDS FOR PERIODS OF HIGH WINDS OVER THE SOUTHWEST THROUGH MIDWEEK. LATER IN THE
PERIOD, SURFACE HIGH PRESSURE IS EXPECTED OVER THE CANADIAN PRAIRIES WHILE THE
SOUTHERN ROCKIES SEE LOWER PRESSURES DOWNSTREAM FROM A DEVELOPING MID-LEVEL
TROUGH. THIS IS FAVORABLE FOR HEAVY SNOW IN THE EAST-CENTRAL AND NORTHEASTERN
ROCKIES AND THE ADJACENT HIGH PLAINS, WITH UPSLOPING LOW-LEVEL FLOW ENHANCING
TOTALS. HEAVY PRECIPITATION IS POSSIBLE FARTHER SOUTH IN THE SOUTHWEST, BUT
THERE IS TOO MUCH UNCERTAINTY TO POST ANY RELATED HAZARDS THERE. FARTHER NORTH,
A SHARP MID-LEVEL TROUGH MAY BRING MUCH BELOW NORMAL TEMPERATURES TO THE
WESTERN HALF OF ALASKA WHILE A POTENTIALLY POTENT STORM FARTHER SOUTH RAISES
THE ODDS FOR HIGH WINDS AND HEAVY PRECIPITATION OVER SOUTH-CENTRAL AND
SOUTHEASTERN ALASKA, BUT THERE IS TOO MUCH UNCERTAINTY TO POST ANY HAZARDS IN
ALASKA AT THIS TIME.
HAZARDS
SLIGHT RISK OF HIGH WINDS IN THE SOUTHWEST FROM ARIZONA THROUGH SOUTHERN
CALIFORNIA, MON-THU, JAN 12-15.
SLIGHT RISK OF HEAVY SNOW OVER THE EAST-CENTRAL AND NORTHEASTERN ROCKIES AND
THE ADJACENT HIGH PLAINS, FRI-SUN, JAN 16-18.
DETAILED SUMMARY
FOR WEDNESDAY JANUARY 07 - SUNDAY JANUARY 11:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR MONDAY JANUARY 12 - SUNDAY JANUARY 18: EARLY WEEK-2, THE ENSEMBLE MEANS
FAVOR A MODERATELY AMPLIFIED PATTERN WITH A SHARP MID-LEVEL TROUGH STRETCHING
FROM WESTERN ALASKA INTO THE CENTRAL NORTH PACIFIC, A DOWNSTREAM MID-LEVEL
RIDGE OVER THE WESTERN CONTIGUOUS UNITED STATES (CONUS), AND A WEAK MID-LEVEL
TROUGH ACROSS THE EASTERN CONUS. THE EUROPEAN ENSEMBLE (ECENS) MEAN IS
STRONGEST WITH THE WESTERN CONUS MID-LEVEL RIDGE WHILE THE GEFS MEAN IS THE
WEAKEST. THE CANADIAN ENSEMBLE (CMCE) MEAN SPLITS THE DIFFERENCE BUT IS CLOSER
TO THE MORE AMPLIFIED ECENS MEAN. A COMPROMISE OF THE MODELS IS FAVORED, BUT IN
ANY CASE, THESE DIFFERENCES WOULD NOT RESULT IN DRAMATIC DIFFERENCES IN THE
RESULTING SENSIBLE WEATHER. THIS PATTERN REMAINS IN PLACE WITH SOME
AMPLIFICATION OF THE EASTERN CONUS MID-LEVEL TROUGH UNTIL THE MIDDLE OF THE
PERIOD, WHEN THE PATTERN STARTS TO RETROGRADE. BY THE END OF THE PERIOD, THE
ENSEMBLE MEANS BUILD A MID-LEVEL RIDGE INTO THE UPPER NORTH PACIFIC, WHICH
ALLOWS MID-LEVEL HEIGHTS TO BUILD INTO ALASKA BUT DROP OVER THE WESTERN CONUS.
THIS RESULTS IN A RELATIVELY WEAK POSITIVELY-TILTED MID-LEVEL TROUGH STRETCHING
FROM NORTH OF THE GREAT LAKES THROUGH THE INTERIOR WEST. THE GEFS MEAN IS
STRONGER THAN THE ECENS AND CMCE MEANS OVER THE INTERIOR WEST, BUT THE ECENS
AND CMCE MEANS SHOW A SECONDARY 500-HPA HEIGHT MINIMUM FROM THE SOUTHERN GREAT
BASIN THROUGH SOUTHERN CALIFORNIA WHICH RETROGRADES OFF THE WEST COAST NEAR THE
END OF THE PERIOD. THE CMCE AND ECENS MEANS WOULD RESULT IN A PATTERN FAVORING
HEAVIER PRECIPITATION OVER AND NEAR THE SOUTHERN ROCKIES, AND TO A LESSER
EXTENT FARTHER NORTH NEAR THE CENTRAL AND NORTHERN FRONT RANGE AND ADJACENT
HIGH PLAINS. MEANWHILE, OVER THE EASTERN HALF OF THE CONUS, THE MID-LEVEL
TROUGH SHOULD DIMINISH LATER IN THE WEEK AS A FLAT MID-LEVEL RIDGE IS
ESTABLISHED FROM THE LOWER MISSISSIPPI VALLEY, THE SOUTHEAST, AND POSSIBLY INTO
THE MID-ATANTIC REGION. WHILE THE ENSEMBLE MEANS ARE IN DECENT AGREEMENT
OVERALL, A FEW DETERMINISTIC MODEL RUNS SHOW MID-LEVEL FEATURES THAT ARE MORE
AMPLIFIED AND/OR PERSISTENT, INTRODUCING ADDITIONAL UNCERTAINTY INTO THE WEEK-2
HAZARDS FORECAST.
AT THE START OF WEEK-2, THE MID-LEVEL RIDGE OVER THE INTERIOR WEST SHOULD
ESTABLISH A STRONG SURFACE HIGH PRESSURE SYSTEM CENTERED OVER THE ROCKIES. THE
DETERMINISTIC EUROPEAN MODEL (ECMWF) IS STRONGEST WITH THIS FEATURE, SHOWING
SURFACE PRESSURES APPROACHING 1050 HPA IN A FEW SPOTS ACROSS THE CENTRAL
ROCKIES. THE OTHER ENSEMBLE MEANS AND OTHER DETERMINISTIC MODELS ARE NOT AS
STRONG, BUT ALL SHOW PRESSURES TOPPING 1040 HPA. MEANWHILE, MID-LEVEL HEIGHTS
ARE FORECAST TO BE CLOSER TO NORMAL FARTHER SOUTH TOWARD MEXICO AND THE
ADJACENT PACIFIC, RESULTING IN LOWER SURFACE PRESSURES OVER THE SOUTHWEST. MOST
MODEL SOLUTIONS SHOW SURFACE PRESSURES BELOW 1024 MB IN PARTS OF SOUTHERN
ARIZONA AND SOUTHERN CALIFORNIA AT THE BEGINNING OF THE PERIOD. THIS RESULTS IN
A TIGHT PRESSURE GRADIENT OVER PORTIONS OF THE SOUTHWEST, INCREASING THE ODDS
FOR PERIODS OF HIGH WINDS ACROSS THE REGION. THE PROBABILISTIC EXTREMES TOOL
(PET) FROM THE ECENS CONTINUES TO SHOW ELEVATED ODDS FOR SUSTAINED WINDS
REACHING THE TOP 15 PERCENT OF CLIMATOLOGY, TOPPING OUT AT OVER 60 PERCENT IN
PARTS OF ARIZONA. THE PETS FROM THE GEFS AND CMCE ARE MUCH LESS IMPRESSIVE, BUT
THE CMCE HAS MOVED IN THE DIRECTION OF THE ECENS PET TODAY, SUPPORTING AN
EXTENSION OF THE SLIGHT RISK OF HIGH WINDS FARTHER TO THE EAST TO COVER
SOUTHERN CALIFORNIA, SOUTHERNMOST NEVADA, AND MUCH OF ARIZONA. AS THE MID-LEVEL
PATTERN BEGINS TO RETROGRADE TOWARD THE MIDDLE OF WEEK-2, THE SURFACE HIGH
PRESSURE OVER THE ROCKIES BEGINS TO LIFT NORTHWARD AND DISSIPATE, RELAXING THE
PRESSURE GRADIENT OVER THE SOUTHWEST AND REDUCING THE ODDS FOR HIGH WINDS
THEREAFTER.
LATER WEEK-2, 500-HPA HEIGHTS BEGIN TO BUILD A FLAT RIDGE OVER THE
SOUTH-CENTRAL AND SOUTHEASTERN CONUS, PUSHING THE EASTERN CONUS MID-LEVEL
TROUGH NORTHWARD TO SOUTHERN CANADA. AT THE SAME TIME, THE MID-LEVEL RIDGE
INITIALLY OVER THE WESTERN CONUS BEGINS TO RETROGRADE, BUILDING TOWARD THE
CENTRAL NORTH PACIFIC AND INTO ALASKA. THIS RESULTS IN LOWERING 500-HPA HEIGHTS
OVER THE WESTERN CONUS, ESTABLISHING AN POSITIVELY-TILTED ANOMALOUS MID-LEVEL
TROUGH WITH AN AXIS REACHING FROM SOUTHERN CANADA THROUGH MUCH OF THE WESTERN
CONUS. ADDITIONALLY, THE CMCE AND ECENS MEANS SHOW A SECONDARY 500-HPA HEIGHT
MINIMUM FORMING OVER THE FAR SOUTHWESTERN CONUS LATER WEEK-2 WHICH RETROGRADES
SLIGHTLY AS THE PERIOD ENDS. THESE MID-LEVEL FEATURES ENGENDER RELATIVELY HIGH
SURFACE PRESSURES ABOVE THE TROUGH AXIS IN THE CANADIAN PRAIRIES, AND LOWER
SURFACE PRESSURES UPSTREAM FROM THE SOUTHWESTERN CONUS MID-LEVEL TROUGH ACROSS
THE SOUTHERN ROCKIES. IF THESE FEATURES EVOLVE AS FORECAST, THE ODDS FOR HEAVY
SNOW INCREASE ALONG THE FRONT RANGE OF THE CENTRAL AND NORTHERN ROCKIES AND THE
ADJACENT HIGH PLAINS DUE TO THE COMBINATION OF CYCLONICALLY-CURVED MID-LEVEL
FLOW AND LOWER-LEVEL UPSLOPING WINDS. THE DETERMINISTIC MODEL AND ENSEMBLE MEAN
SNOWFALL FORECASTS ARE NOT PARTICULARLY HEAVY AT THIS TIME, BUT THE GEFS PET
SHOWS INCREASED ODDS FOR SNOW WATER EQUIVALENT TOTALS AMONG THE TOP 15 PERCENT
OF THE CLIMATOLOGICAL ENVELOPE FOR THE LAST FEW DAYS OF WEEK-2. THERE ARE NO
SNOW WATER EQUIVALENT PETS DERIVED FROM EITHER THE ECENS OR CMCE, BUT THE
PATTERN FORECAST BY THEIR ENSEMBLE MEANS WOULD BE MORE FAVORABLE FOR HEAVY SNOW
IN THE REGION THAN THE GEFS MEAN, BOOSTING FORECAST CONFIDENCE SOMEWHAT.
FARTHER SOUTH, CLOSER TO THE SOUTHWESTERN CONUS MID-LEVEL TROUGH, THE PETS AND
SOME DETERMINISTIC MODELS SHOW INCREASED POTENTIAL FOR HEAVY PRECIPITATION OVER
THE SOUTHERN ROCKIES AND SOME ADJACENT AREAS AT THE SAME TIME, BUT THERE IS TOO
MUCH UNCERTAINTY TO POST ANY RELATED HAZARDS IN THE SOUTHWEST AT THIS TIME.
THERE ARE NO HAZARDS POSTED FOR ALASKA AGAIN TODAY, BUT SOME GUIDANCE SHOWS THE
POTENTIAL FOR A FEW HAZARDS TO AFFECT DIFFERENT PARTS OF THE STATE. HOWEVER,
THERE IS A GREAT DEAL OF MODEL SPREAD AND THE PREPONDERANCE OF THE TOOLS KEEP
CONDITIONS BELOW HAZARDS THRESHOLDS. A SHARP MID-LEVEL TROUGH INITIALLY ALONG
THE WESTERN TIER OF THE STATE COULD RESULT IN MUCH BELOW NORMAL TEMPERATURES
OVER SOME OF THE CENTRAL AND WESTERN SECTIONS OF THE MAINLAND. EARLY WEEK-2,
MOST DETERMINISTIC MODELS AND ENSEMBLE MEANS DEPICT TEMPERATURES RANGING FROM
10 TO 30 DEG. F BELOW NORMAL OVER AT LEAST SOME PORTION OF THE CENTRAL,
WEST-CENTRAL, AND SOUTHWESTERN PARTS OF THE STATE. A FEW SOLUTIONS SHOW
TEMPERATURES REACHING AS MUCH AS 45 DEG. F BELOW NORMAL, BUT THESE ARE MINORITY
OUTLIERS AT THIS TIME, AND THERE HAVE BEEN OTHER RECENT MODEL RUNS SHOWING
TEMPERATURES NOT SIGNIFICANTLY BELOW NORMAL. SIMILARLY, A FEW DETERMINISTIC
RUNS HAVE SHOWN TEMPERATURES DROPPING TO AS LOW AS -55 DEG. F IN SPORTS, BUT
THE PREPONDERANCE OF THE MODELS, INCLUDING THE ENSEMBLE MEANS, KEEP READINGS
ABOVE -40 DEG. F. GIVEN THE WIDE RANGE OF MODEL SOLUTIONS, NO HAZARDS ARE
POSTED AT THIS TIME, ALTHOUGH THE SITUATION WILL CONTINUE TO BE MONITORED.
THERE IS ALSO UNCERTAINTY REGARDING THE POTENTIAL FOR A POTENT STORM SYSTEM TO
AFFECT SOME OF THE SOUTHERN PARTS OF THE STATE. MOST MODEL SOLUTIONS HAVE LOW
SURFACE PRESSURE STARTING THE WEEK OVER OR NEAR THE GULF OF ALASKA WITH HIGHER
SURFACE PRESSURES ACROSS THE INTERIOR OF ALASKA AND WESTERN CANADA, BUT THE
STRENGTH AND LOCATION OF ANY STORM SYSTEM THAT FORMS AND THE HIGH SURFACE
PRESSURES TO THE NORTH AND EAST ARE HIGHLY UNCERTAIN. THE 0Z DETERMINISTIC
ECMWF DEPICTS A 969 HPA LOW PRESSURE CENTER IN THE GULF OF ALASKA EARLY WEEK-2
WHILE SURFACE PRESSURES APPROACH 1020 HPA IN FAR SOUTHEASTERN ALASKA. THIS
PATTERN WOULD ENGENDER HIGH WINDS AND HEAVY PRECIPITATION ACROSS SOUTH-CENTRAL
AND SOUTHEASTERN ALASKA, ALONG WITH HEAVY SNOWFALL AWAY FROM THE IMMEDIATE
COAST. IN CONTRAST, THE ENSEMBLE MEANS ALL KEEP THE SURFACE LOW PRESSURE CENTER
ABOVE 990 MB, AND BOTH THE DETERMINISTIC CANADIAN AND CMCE MEAN PLACE A
RELATIVELY WEAK LOW PRESSURE CENTER INLAND OVER THE SOUTHEASTERN MAINLAND,
WHICH RESULTS IN LESS UNSETTLED WEATHER. THE PETS DERIVED FROM THE ECENS AND
CMCE SHOW ENHANCED ODDS FOR WINDS REACHING THE 15TH PERCENTILE OF THE
CLIMATOLOGICAL ENVELOPE, BUT THE RAW WIND FORECASTS FROM THE ENSEMBLE MEANS AND
MOST DETERMINISTIC MODELS KEEP PRECIPITATION AND WINDS BELOW HAZARDS
THRESHOLDS. GIVEN THE BROAD ARRAY OF MODEL SOLUTIONS, NO WIND OR PRECIPITATION
HAZARDS ARE POSTED IN ALASKA AT THIS TIME.
FORECASTER: RICH TINKER
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